Hi!
I'd be stunned if this was actually a server problem, and not a client-side problem related to grabs. Which window manager do you use? Does changing it fix anything?
I use openbox. However, I don't think it's a client side problem, as no grabs can prevent Ctrl-Alt-F1 and such to work. The freezes seem random -- the last one I experienced (after ~week of flawless work) occured after I opened a file with kate. Regards Jiri Palecek